U.S. patent number 6,504,258 [Application Number 09/876,976] was granted by the patent office on 2003-01-07 for vibration based downhole power generator.
This patent grant is currently assigned to Halliburton Energy Services, Inc.. Invention is credited to Russell Irving Bayh, III, Robert Ken Michael, Paul David Ringgenberg, Clark Edward Robison, Roger Lynn Schultz.
United States Patent |
6,504,258 |
Schultz , et al. |
January 7, 2003 |
**Please see images for:
( Certificate of Correction ) ** |
Vibration based downhole power generator
Abstract
A downhole power generator produces electrical power for use by
downhole tools. In a described embodiment, a downhole power
generator includes a member that is vibrated in response to fluid
flow through a housing. Vibration of the member causes a power
generating assembly to generate electrical power.
Inventors: |
Schultz; Roger Lynn (Denton,
TX), Ringgenberg; Paul David (Carrollton, TX), Robison;
Clark Edward (Plano, TX), Michael; Robert Ken (Plano,
TX), Bayh, III; Russell Irving (Carrollton, TX) |
Assignee: |
Halliburton Energy Services,
Inc. (Dallas, TX)
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Family
ID: |
23961762 |
Appl.
No.: |
09/876,976 |
Filed: |
June 8, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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493801 |
Jan 28, 2000 |
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Current U.S.
Class: |
290/1R;
310/36 |
Current CPC
Class: |
F03G
7/08 (20130101); E21B 41/0085 (20130101); H02N
2/185 (20130101); E21B 28/00 (20130101) |
Current International
Class: |
E21B
28/00 (20060101); E21B 41/00 (20060101); H01L
41/00 (20060101); H01L 41/12 (20060101); H01L
41/113 (20060101); H02P 009/04 () |
Field of
Search: |
;290/1R ;175/56,104
;310/311,334,339,15,26,30,36 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2626729 |
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Aug 1989 |
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FR |
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2153410 |
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Aug 1985 |
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GB |
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09163771 |
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Jun 1997 |
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JP |
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Other References
Etrema Products, Inc., Product Brochure, Undated. .
John V. Bouyoucos, "Self-Excited Hydrodynamic Oscillators",
NR-014-903, Technical Memorandum, Dated Jul. 31, 1955..
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Primary Examiner: Waks; Joseph
Attorney, Agent or Firm: Herman; Paul I. Smith; Marlin R.
Konneker; J. Richard
Parent Case Text
This is a continuation, of application Ser. No. 09/493,801, filed
Jan. 28, 2000, abandoned such prior application being incorporated
by reference herein in its entirety.
Claims
What is claimed is:
1. A downhole power generator, comprising: a housing having a first
axial flow passage formed therethrough; and a power generating
structure including a nozzle and a power generating assembly, the
nozzle having a second flow passage formed therethrough and in
entirely non-valved communication with the first flow passage, the
second flow passage having a longitudinal axis, the nozzle
vibrating along the longitudinal axis in response to fluid flow
through the first and second flow passages, and the power
generating assembly producing electrical power in response to the
nozzle vibration, the power generating assembly including a magnet
and a coil, one of the magnet and the coil being attached to the
nozzle, and the other of the magnet and the coil being attached to
the housing so that, as the nozzle vibrates relative to the
housing, relative displacement is produced between the coil and the
magnet.
2. The downhole power generator according to claim 1, wherein fluid
flow through the second flow passage creates a pressure
differential across the nozzle, the pressure differential varying
and biasing the nozzle in the direction of the fluid flow.
3. The downhole power generator according to claim 2, further
comprising a bias member biasing the nozzle in a direction opposite
to the direction of the fluid flow.
4. A method of generating power downhole, the method comprising the
steps of: flowing fluid in a first direction through a housing
interconnected in a tubular string in a well; vibrating a structure
within the housing in response to the fluid flow through the
housing; generating electrical power in response to the structure
vibration; retrievably securing the structure relative to the
housing; and retrieving the structure from the tubular string
separate from the housing while the housing is positioned
downhole.
5. A method of generating power downhole, the method comprising the
steps of: flowing fluid in a first direction through a housing
interconnected in a tubular string in a well; vibrating a structure
within the housing in response to the fluid flow through the
housing; and generating electrical power in response to the
structure vibration, wherein the structure includes a coil and a
magnet, wherein the vibrating step further comprises displacing the
coil relative to the magnet, thereby producing an electric current
in the coil in the generating step, wherein the displacement of the
coil relative to the magnet has a natural frequency, and wherein
the vibrating step further comprises displacing the coil relative
to the magnet at the natural frequency.
6. The method according to claim 5, wherein the structure further
includes an elongated member secured at one end relative to the
housing, displacement of the other end of the member relative to
the housing having substantially the same natural frequency as
displacement of the coil relative to the magnet, and wherein the
vibrating step further comprises displacing the other end of the
member relative to the housing at the natural frequency.
7. A method of generating power downhole, the method comprising the
steps of: flowing fluid in a first direction through a housing
interconnected in a tubular string in a well; vibrating a structure
within the housing in response to the fluid flow through the
housing; and generating electrical power in response to the
structure vibration, wherein the structure includes a
magnetostrictive material positioned proximate a coil, and wherein
the vibrating step comprises inducing strain in the
magnetostrictive material, thereby producing an electric current in
the coil in the generating step.
8. A method of generating power downhole, the method comprising the
steps of: flowing fluid in a first direction through a housing
interconnected in a tubular string in a well; vibrating a structure
within the housing in response to the fluid flow through the
housing; generating electrical power in response to the structure
vibration; and electrically interconnecting the structure to a
power-consuming downhole tool via an inductive coupling.
9. A method of generating power downhole, the method comprising the
steps of: flowing fluid in a first direction through a housing
interconnected in a tubular string in a well; vibrating a structure
within the housing in response to the fluid flow through the
housing; and generating electrical power in response to the
structure vibration, wherein the structure comprises a member,
wherein the vibrating step further comprises displacing the member
relative to the housing in response to fluid flow through the
member, and wherein the generating step further comprises inducing
a strain in a magnetostrictive material proximate a coil, thereby
creating an electric current in the coil, in response to
displacement of the member relative to the housing.
10. A method of generating power downhole, the method comprising
the steps of: flowing fluid in a first direction through a housing
interconnected in a tubular string in a well; vibrating a structure
within the housing in response to the fluid flow through the
housing, the structure having an interior; generating electrical
power in response to the structure vibration; and regulating the
vibration of the structure in response to the fluid flow through
the housing, the regulating step being performed in response to a
change in the fluid flow through the housing effected by creating
relative movement between the structure and a member projecting
into the interior of the structure.
11. A downhole power generator, comprising: a housing having a
first flow passage formed therethrough; and a power generating
structure including a power generating assembly and a vibrating
member, the member vibrating in response to fluid flow through the
first flow passage, and the power generating assembly generating
electrical power in response to vibration of the member, wherein
the power generating assembly includes a coil positioned proximate
a magnetostrictive material, vibration of the member causing strain
in the magnetostrictive material.
12. A downhole power generator, comprising: a housing having a
first flow passage formed therethrough; and a power generating
structure including a power generating assembly and a vibrating
member, the member vibrating in response to fluid flow through the
first flow passage, and the power generating assembly generating
electrical power in response to vibration of the member, wherein
the member has a second flow passage formed therethrough in
communication with the first flow passage, the member vibrating in
response to fluid flow through the second flow passage, and wherein
the power generating assembly includes a magnetostrictive material
disposed between the member and the housing so that, as the member
is vibrated, strain is induced in the magnetostrictive
material.
13. A downhole power generator, comprising: a housing having a
first flow passage formed therethrough; and a power generating
structure including a power generating assembly and a vibrating
member, the member vibrating in response to fluid flow through the
first flow passage, and the power generating assembly generating
electrical power in response to vibration of the member, wherein
the power generating structure is retrievably secured relative to
the housing while the housing is positioned downhole.
14. A downhole power generator, comprising: a housing having a
first flow passage formed therethrough; and a power generating
structure including a power generating assembly and a vibrating
member, the member vibrating in response to fluid flow through the
first flow passage, and the power generating assembly generating
electrical power in response to vibration of the member, wherein
the power generating structure is electrically interconnected to
the housing via an inductive coupling.
15. A downhole power generator comprising: a housing having a first
flow passage formed therethrough; a power -generating structure
including a power generating assembly and a vibrating member, the
member vibrating in response to fluid flow through the first flow
passage, and the power generating assembly generating electrical
power in response to vibration of the member; and a regulating
member extending into the vibrating member, the regulating member
regulating the flow responsive vibration of the vibrating member,
and the regulating member being responsive to a change in the fluid
flow through the housing.
16. The downhole power generator according to claim 15, wherein the
regulating member regulates a velocity of the fluid flow in the
housing.
17. The downhole power generator according to claim 15, wherein the
regulating member varies a flow area in the housing.
18. The downhole power generator according to claim 15, wherein
there is a relative displacement between the regulating member and
the vibrating member in response to the change in the fluid flow
through the housing.
19. A downhole power generator, comprising: a generally tubular
housing having an axial flow passage formed therethrough; and a
power generating structure including a power generating assembly
and an elongated member extending into the flow passage, at least
one end of the member vibrating laterally relative to the housing
in response to fluid flow through the flow passage, and the power
generating assembly being attached to the member so that as the
member vibrates, the power generating assembly generates electrical
power, wherein the power generating assembly includes a coil and a
magnetostrictive material, vibration of the member inducing strain
in the magnetostrictive material and generating an electric current
in the coil.
20. A downhole power generator, comprising: a generally tubular
housing having an axial flow passage formed therethrough; and a
power generating structure including a power generating assembly
and an elongated member extending into the flow passage, at least
one end of the member vibrating laterally relative to the housing
in response to fluid flow through the flow passage, and the power
generating assembly being attached to the member so that as the
member vibrates, the power generating assembly generates electrical
power, wherein the power generating assembly includes a mass and a
piezoelectric material, vibration of the member causing the mass to
induce strain in the piezoelectric material.
21. A downhole power generator, comprising: a housing having a
first axial flow passage formed therethrough; and a power
generating structure including a nozzle and a power generating
assembly, the nozzle having a second flow passage formed
therethrough in communication with the first flow passage, the
nozzle vibrating axially relative to the housing in response to
fluid flow through the first and second flow passages, the power
generating assembly producing electrical power in response to the
nozzle vibration, and wherein the power generating assembly
includes a magnetostrictive material disposed proximate a coil and
axially between at least a portion of the nozzle and at least a
portion of the housing so that, as the nozzle axially vibrates
relative to the housing, strain is repetitively induced in the
magnetostrictive material, thereby producing a magnetic field about
the coil.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to operations and equipment
utilized in conjunction with subterranean wells and, in an
embodiment described herein, more particularly provides a method
and apparatus for generating electrical power downhole.
Power for use in a downhole environment has generally in the past
been either stored in a device, such as a battery, and conveyed
downhole or it has been transmitted via conductors, such as a
wireline, from the space or another remote location. As is well
known, batteries have the capability of storing only a finite
amount of power therein and have environmental limits, such as
temperature, on their use. Additionally, batteries are not readily
recharged downhole.
Electrical conductors, such as those in a conventional wireline,
provide a practically unlimited amount of power, but require
special facilities at the surface for deployment and typically
obstruct the production flowpath, thereby preventing the use of
safety valves, limiting the flow rate of fluids through the
flowpath, etc. while the conductors are in the flowpath. Thus,
wireline operations are typically carried out prior to the
production phase of a well, or during remedial operations after the
well has been placed into production.
What is needed is a method of generating electrical power downhole.
The method should not require that power be stored in a device and
then convened downhole where it is difficult to recharge. The
method should also not require that power be transmitted from a
remote location via one or more conductors positioned in a
production flowpath of a well. It is accordingly an object of the
present invention to provide a method whereby power is generated
downhole, and to provide an apparatus for such power
generation.
SUMMARY OF THE INVENTION
In carrying out the principles of the present intention, in
accordance with an embodiment thereof, a downhole power generator
is provided in which fluid flow therethrough causes vibration of a
member therein. Vibration of the member is used to produce
electrical power.
In one aspect of the present invention, the member is elongated and
extends into a flow passage formed through a housing. As fluid
flows through the flow passage, the member vibrates. The member may
be secured to the housing at one end, with the other end facing
into the fluid flow. Alternatively, the secured end may face in the
direction of the fluid flow. The member may be configured to
enhance the amplitude and/or frequency of its vibration.
Vibration of the member may be used to generate electrical power in
a variety of manners. A power generating assembly may be attached
to the member so that, as the member vibrates, the power generating
assembly is displaced therewith. Displacement of the power
generating assembly causes electrical power to be generated.
For example, the power generating assembly may include a coil and a
magnet, with relative displacement being produced between the coil
and the magnet as the member vibrates. The power generating
assembly may include a piezoelectric material and a mass, with the
mass bearing on the piezoelectric material and inducing strain
therein as the member vibrates. The power generating assembly may
include a piezoelectric material applied to the member, so that
strain is induced in the piezoelectric material as the member
flexes when it vibrates. The power generating assembly may include
a coil and a magnetostrictive material, with strain being induced
in the magnetostrictive material as the member vibrates.
In another aspect of the present invention, the member may have a
flow passage formed through it, with the member vibrating when
fluid is flowed through its flow passage. The member may be in the
form of a nozzle or venturi. A varying pressure differential is
created across the member as the fluid flows therethrough, causing
the member to vibrate. Again, a variety of methods may be used to
produce electrical power from the vibration of the member,
including inducing strain in a piezoelectric material, inducing
strain in a magnetostrictive material, displacing a coil relative
to a magnet, etc.
In a further aspect of the present invention, vibration of the
member in response to fluid flow may be regulated downhole. For
example, the effect of changes in the fluid flow may be regulated
by maintaining a velocity of the fluid flow within predetermined
limits. Such velocity maintenance may be accomplished, for example,
by varying a flow area in response to chances in the fluid flow
rate through the flow passage.
These and other features, advantages, benefits and objects of the
present invention will become apparent to one of ordinary skill in
the art upon careful consideration of the detailed description of
representative embodiments of the invention hereinbelow and the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic cross-sectional view of a method of
generating power downhole embodying principles of the present
invention;
FIGS. 2A-F are cross-sectional views of successive axial sections
of a first apparatus usable in the method of FIG. 1;
FIG. 3 is a cross-sectional view of a portion of the first
apparatus taken alone line 3--3 of FIG. 2B;
FIG. 4 is a cross-sectional view of a portion of the first
apparatus taken also line 4--4 of FIG. 2E;
FIG. 5 is a cross-sectional view of a first power generating
assembly usable in the first apparatus;
FIG. 6 is a cross-sectional view of a second power generating
assembly usable in the first apparatus;
FIG. 7 is a schematic diagram of power generation, storage,
conversion and connection in the first apparatus;
FIGS. 8A & B are cross-sectional views of successive axial
sections of a second apparatus usable in the method of FIG. 1;
FIGS. 9 & 9A are end and cross-sectional views, respectively,
of a first alternate nose for use with the first or second
apparatus;
FIG. 10 is an isometric view of a second alternate nose for use
with the first or second apparatus;
FIG. 11 is a cross-sectional view of a third alternate nose for use
with the first or second apparatus;
FIG. 12 is a cross-sectional view of a fourth alternate nose for
use with the first or second apparatus;
FIG. 13 is a schematic cross-sectional view of a third apparatus
usable in the method of FIG. 1;
FIG. 14 is a schematic cross-sectional view of a fourth apparatus
usable in the method of FIG. 1;
FIG. 15 is a schematic cross-sectional view of a fifth apparatus
usable in the method of FIG. 1; and
FIG. 16 is a schematic cross-sectional view of an alternate
configuration of the first apparatus.
DETAILED DESCRIPTION
Representatively illustrated in FIG. 1 is a method 10 which
embodies principles of the present invention. In the following
description of the method 10 and other apparatus and methods
described herein, directional terms, such as "above", "below",
"upper", "lower", etc., are used for convenience in referring to
the accompanying draftings. Additionally, it is to be understood
that the various embodiments of the present invention described
herein may be utilized in various orientations, such as inclined,
inverted, horizontal, vertical, etc., without departing from the
principles of the present invention.
The method 10 is described herein as being performed in conjunction
with a producing well in which fluid is produced from a formation
12 and into a tubular string 14, and is then flowed through the
tubular string to the earth's surface. However, it is to be clearly
understood that principles of the present invention may be
incorporated in other methods, for example, where fluid is injected
into a formation or circulated in the well, such as during drilling
operations, where fluids pass from a relatively high pressure
source to a relatively low pressure zone within the well, or where
fluid flows from a pump or other "artificial" pressure source, etc.
Thus, it is not necessary, in keeping with the principles of the
present invention, for fluid to be produced through a tubular
string.
In the method 10 as depicted in FIG. 1, fluid from the formation 12
enters the tubular string 14 through a valve 16 or other opening in
the tubular string and flows upwardly in the tubular string.
Interconnected in the tubular string 14 is a downhole power
generator 18 through which the fluid flows. In one important aspect
of the present invention, this fluid flow through the power
generator 18 causes it to generate electrical power. This
electrical power may then be used to operate a downhole tool, such
as a valve 20 interconnected in the tubular string 14. It is to be
clearly understood that the naive 20 is used merely as an example
of the wide variety of downhole tools that may be powered by the
generator 18, such as sensors, samplers, flow control devices,
communication devices, etc.
Electric lines or conductors 22 may be used to electrically connect
the power generator 18 to the valve 20, enabling the valve to be
remotely located relative to the power generator. Alternatively,
the power generator 18 and valve 20 (or other downhole tool) may be
integrally formed or directly connected to each other. Furthermore,
the power generator 18 may be positioned above or below the valve
20, or in any other position relative to the valve.
Referring additionally now to FIGS. 2A-F, a downhole power
generator 26 embodying principles of the present invention is
representatively illustrated. The power generator 26 may be used
for the power generator 18 in the method 10 described above. Of
course, the power generator 26 may be used in many other methods,
without departing from the principles of the present invention.
The power generator 26 includes an outer generally tubular housing
assembly 28 having a flow passage 30 formed generally axially
therethrough. The housing assembly 28 is appropriately configured
for interconnection in a tubular string, such as the tubular string
14 in the method 10, such that fluid flow through the tubular
string also flows through the passage 30. Referring briefly to FIG.
3, it may be seen that the passage 30 is diverted between a central
portion of the housing assembly 28 and an outer portion thereof via
windows 32 formed radially through an inner generally tubular
mandrel portion 34 of the housing assembly. Generally annular voids
36 are formed between the mandrel 34 and the portion of the housing
assembly 28 outwardly overlying the mandrel, and these voids are
part of the flow passage 30.
Releasably engaged with a profile 38 internally formed in the
mandrel 34 is a conventional lock 40 of the type well known to
those skilled in the art. For example, the lock 40 may be a
Halliburton X-type lock, or any other type of lock. However, it is
to be clearly understood that any releasable attachment means may
be used in the power generator 26, without departing from the
principles of the present invention.
A power generating structure 42 is attached to the lock 40 at a
lower end thereof. The power generating structure 42 extends
downwardly from the lock 40 and into the passage 30 below the
mandrel 34. Note that the power generating structure 42 is axially
elongated and has one end (its upper end as depicted in FIGS. 2A-F)
secured against displacement relative to the housing assembly 28 by
the lock 40 and has its other end (its lower end as depicted in
FIGS. 2A-F) extending into the passage 30.
Thus, as shown in FIGS. 2A-F, the power generating structure 42 has
its lower end facing into the fluid flow through the passage 30, if
the fluid flow is directed upwardly through the housing assembly
28. This would be the case if the power generator 26 were to be
used as shown in FIGS. 2A-F for the power generator 18 in the
method 10. However, it is to be clearly understood that fluid may
flow downwardly through the passage 30, such as in an injection
operation, or the power generator 26 may be differently configured
so that the lower end of the power generating structure 42 faces in
the direction of the fluid flow through the housing, assembly 28,
or in another direction, without departing, from the principles of
the present invention.
It will be readily appreciated by one skilled in the art that, when
fluid flows through the passage 30 about the power generating
structure 42, the lower end of the power generating structure will
be deflected somewhat laterally relative to the housing assembly
28. This lateral deflection will occur repetitively, with the lower
end of the power generating structure 42 oscillating back and forth
within the housing assembly 28. Thus, fluid flow through the
passage 30 causes the power generating structure 42 to vibrate.
The power generating structure 42 includes an elongated member 44.
As depicted in FIGS. 2D & E, the member 44 is generally tubular
and is made of a relatively rigid material, such as steel. It will
be readily appreciated by one skilled in the art that the frequency
at which the power generating structure 42 vibrates in response to
the fluid flow through the passage 30 may be varied by changing the
configuration and/or material of the member 44. For example, the
member 44 may be made of a less rigid material to decrease the
vibration frequency, or the wall thickness of the member may be
increased to increase the vibration frequency, etc. Therefore, it
is to be clearly understood that the configuration and/or the
material of the member 44 may be changed, and the frequency of the
power generating structure 42 vibration may be changed, without
departing from the principles of the present invention.
Attached at a lower end of the member 44 is a substantially hollow
nose 46. The nose 46 may be made of a relatively erosion resistant
material to resist the effects of the fluid flow through the
passage 30 impinging on the nose. It will be readily appreciated
that the mass of the nose 46 may be adjusted to vary the frequency
at which the power generating structure 42 vibrates in response to
the fluid flow through the passage 30.
Referring additionally now to FIG. 4, a cross-sectional view taken
through the nose 46 along line 4--4 of FIG. 2E is representatively
illustrated. In this view it may be seen that the nose 46 contains
multiple power generating assemblies 48 therein. As depicted in
FIG. 4, there are three power generating assemblies 48 within the
nose 46, with the assemblies being equally spaced angularly with
respect to each other.
The power generating assemblies 48 respond to the vibration of the
power generating structure 42 by generating electrical power. The
varied angular distribution of the power generating assemblies 48
ensures that, no matter the lateral direction of the vibration, at
least one of the assemblies will appropriately respond to the
vibration by generating electrical power therefrom.
Any number and any orientation of the assemblies 48 may be used,
without departing from the principles of the present invention. For
example, there could be four of the assemblies 48, instead of
three, and they could be differently angularly spaced, such as by
positioning the assemblies orthogonal to each other, etc.
FIG. 4 depicts only one level of the assemblies 48 within the nose
46, but there may be multiple levels above or below the one shown
in FIG. 4. For example, there could be three levels of three
assemblies 48 each, for a total of nine assemblies within the nose
46. All of the assemblies 48 could be oriented in the same
direction, or they could be oriented in a different direction on
each level, the assemblies could each be oriented differently on
the same level, etc. For example, each level could include one of
the assemblies 48, with each assembly being positioned orthogonal
to the assemblies on the next adjacent levels, etc.
Representatively illustrated in FIG. 5 is an example of a power
generating assembly 50 which may be used for one or more of the
assemblies 48 in the power generator 26. The assembly 50 includes a
central generally cylindrical magnet 52 and a coil 54
circumscribing the magnet. The coil 54 is biased toward a central
axial position relative to the magnet 52 by two opposing springs or
other bias members 56.
It will be readily appreciated that, when there is relative axial
displacement between the coil 54 and the magnet 52, an electric
current will be generated in the coil. If the assembly 50 is used
in the power generator 26, displacement of the coil 54 relative to
the magnet 52 will occur when the structure 42 vibrates in response
to fluid flow through the passage 30. The springs 56 ensure that
the coil 54 is appropriately positioned relative to the magnet 52,
so that when the member 44 displaces laterally, the coil will
displace relative to the magnet.
Of course, the assembly 50 may be differently configured, without
departing from the principles of the present invention. For
example, the magnet 52 may be an electromagnet. As another example,
the coil 54 may be rigidly mounted, with the magnet 52 displacing
in response to vibration of the assembly 50.
The power generating structure 42 has a natural frequency of
vibration at which the member 44 displaces laterally in response to
the fluid flow through the passage 30. This natural frequency may
be adjusted using techniques described above, such as changing the
rigidity of the member 44, changing the mass of the nose 46, etc.
It will be readily appreciated that the displacement of the coil 54
relative to the magnet 52 also has a natural frequency, which may
also be adjusted, for example, by changing the spring rate of the
springs 56, changing the mass of the coil 54, etc. It will further
be appreciated that increased displacement of the coil 54 relative
to the magnet 52 may be achieved by matching the natural frequency
of the assembly 50 to the natural frequency of the power generating
structure 42. In this way, the power generating structure 42 will
vibrate at a frequency that will produce maximum electrical power
output from each of the assemblies 48.
Representatively illustrated in FIG. 6 is another example of a
power generating assembly 58 which may be used for one or more of
the assemblies 48 in the structure 42. The assembly 58 includes a
mass 60 positioned between piezoelectric crystals 62. As the
assemble 58 is vibrated laterally, the mass 60 bears on alternating
ones of the crystals 69, thereby alternately inducing strain in
each of the crystals.
As is well known, piezoelectric materials generate an electric
current when strain is induced therein. Thus, when the assembly 58
is vibrated laterally, electric current is produced by the crystals
62.
It is not necessary for the assembly 50 or 58 to be used for one or
more of the assemblies 48, since other types of power generating
assemblies may be used without departing from the principles of the
present invention. Furthermore, it is not necessary for the power
generating assemblies 48 to be positioned within the nose 46 of the
structure 42. For example, FIG. 2E depicts alternate power
generating assemblies 66, 68, which are distributed along the
length of the member 44.
The power generating assembly 66 includes a piezoelectric material
70 applied to an internal surface of the member 44. The
piezoelectric material 70 is relatively thin as compared to the
wall thickness of the member 44 and may be applied as a film
adhered to the member's surface, or as a coating. An example of a
material which may be suitable for use as the piezoelectric
material 70 is known as PZT. Of course, the piezoelectric material
70 may be otherwise positioned reality e to the member 44, such as
externally, and may be otherwise applied or attached to the member,
without departing from the principles of the present invention.
As the member 44 oscillates laterally in response to fluid flow
through the passage 30, it will be readily appreciated that such
flexing of the member will induce strain in the piezoelectric
material 70. In response to this strain, the piezoelectric material
70 generates an electric current. Thus, as the member 44
repetitively displaces relative to the housing assembly 28, the
power generating assembly 66 produces corresponding repetitive
electric currents.
The power generating assembly 68 includes a magnetostrictive
material 72 positioned within a coil 74, with both the material and
the coil being positioned within the member 44. A suitable material
for the magnetostrictive material 72 is known as Terfenol-D,
available from Etrema Products, Inc. When strain is induced in the
material 72, it produces a magnetic field about the coil 74,
thereby causing an electric current to be generated in the coil. Of
course, the magnetostrictive material 72 and the coil 74 may be
otherwise positioned relative to the member 44 and may be otherwise
configured, without departing from the principles of the present
invention.
As the member 44 oscillates in response to fluid flow through the
passage 30, it will be readily appreciated that strain is induced
in the magnetostrictive material 72. In response to this strain,
the magnetostrictive material 72 generates a magnetic field and an
electric current is produced in the coil 74. Thus, as the member 44
repetitively displaces relative to the housing assembly 28, the
power generating assemble 68 produces corresponding repetitive
electric currents.
Referring again to FIG. 4, the electrical output of the assemblies
48 is conducted via lines or conductors 64 upwardly through the
member 44. For example, if the assembly 50 of FIG. 5 is used for
the assemblies 48, the coil 54 is connected to the conductors 64,
and if the assembly 58 of FIG. 6 is used, the piezoelectric
crystals 62 are connected to the conductors 64. If the alternative
power generating assembly 66 is used, the conductors 64 are
connected to the piezoelectric material 70, and if the alternative
power generating assembly 68 is used, the conductors are connected
to the coil 74, as depicted in FIG. 2E.
As may be seen in FIG. 2D, the conductors 64 are connected to a
power storage and conversion unit 76, which is described in further
detail below. The unit 76 is, in turn, connected to an inductive
coupling 78 of the type well known to those skilled in the art.
As depicted in FIGS. 2A-D, the inductive coupling 78 is connected
to a downhole tool 80 contained within the housing assembly 28.
Alternatively, the inductive coupling 78 may be connected to a
downhole tool remote from the power generator 26, as depicted in
FIG. 1, wherein the valve 20 is connected via lines 22 to the power
generator 18.
The inductive coupling 78 permits convenient electrical connection
and disconnection between the power generating structure 42 and the
remainder of the power generator 26. This arrangement enables the
structure 42 to be retrieved from the well in the event that it
requires maintenance, upgrading, etc., or access is required to the
passage 30 below the structure 42. Of course, other means of
electrically connecting the structure 42 to a downhole tool may be
utilized without departing from the principles of the present
invention. For example, a device known to those skilled in the art
as a "wet connect" may be used, the structure 42 may be directly
connected to the tool 80, etc.
To retrieve the structure 42 from within the power generator 26, a
conventional tool, well known to those skilled in the art, is
engaged with the lock 40, the lock is released from the profile 38,
and the lock and structure are displaced upwardly out of the power
generator. These steps are reversed to replace the structure 42 and
lock 40 in the housing assembly 28. However, it is not necessary,
in keeping with the principles of the present invention, for the
structure 42 to be retrievable or otherwise releasably secured in
the power generator 26.
Referring additionally now to FIG. 7, a schematic diagram of
electrical power generation, storage, conversion and connection in
the power generator 26 is representatively illustrated. In FIG. 7,
the structure 42 is depicted as a power generating device which
produces electrical power in response to vibration. Electrical
power is communicated via conductors 64 from the structure 42 to
the unit 76 as described above.
The unit 76 includes an AC to DC converter 82, an energy storage
device 84 and a DC to AC converter 86. As will be readily
appreciated the electrical power generated in response to vibration
of the member 44 as described above is or the AC type, in that the
current is not constant, but is instead repetitive. although not
necessarily sinusoidal. The converter 82 is used to convert the
generated power to a DC-type output, which is then stored in the
device 84. The device 84 may be a battery or any other type of
energy storage device.
The converter 86 is used to convert an output of the device 84 into
an AC-type signal, since this is the preferred mode of transmitting
power across the inductive coupling 78. However, it is to be
clearly understood that it is not necessary for the unit 76 to
include the specific elements 82, 84, 86 described above, or for
the output of the structure 42 to be converted to a DC-type signal,
stored in an energy storage device, and then converted back into an
AC-type signal. A great variety of other means for converting the
output of the power generating structure 42 into usable electrical
power may be substituted for the representatively illustrated unit
76, without departing from the principles of the present
invention.
Once electrical power has been transmitted across the inductive
coupling 78, it is connected to the tool 80 as described above. The
tool 80 may include an AC to DC converter 88, an energy storage
device 90, such as a batter, a DC to DC converter 92 and
electronics or other electrical equipment to be powered 94. The
equipment 94 may, for example, be a pressure or temperature sensor,
a solenoid used to actuate a valve, a downhole data storage device,
a communication device, etc.
Of course, certain of these elements 88, 90, 92 may not be needed
or desired. For example, if the electrical equipment 94 may be
powered directly from the AC signal transmitted across the
inductive coupling, the converters 88, 92 and energy storage device
90 may not be needed. As another example, if the voltage output of
the energy storage device 90 does not need to be converted prior to
use by the electrical equipment 94, the converter 92 may not be
needed.
It is to be clearly understood that the unit 76 and tool 80 as
described above are given merely as examples of the wide variety of
implementations of the principles of the present invention, and
various changes may be made to their configurations, without
departing from the principles of the present invention. For
example, if the power generator 26 is used for the power generator
18 in the method 10 depicted in FIG. 1, the valve 20 may only have
an electrical actuator therein, with the remaining elements 88, 90,
92 of the tool 80 shown in FIG. 7 being included in the power
generator. Thus, it is not necessary, in keeping with the
principles of the present invention, for the various electrical
elements of the unit 76 or tool 80 to be configured, positioned,
included or arranged as representatively illustrated in FIG. 7.
Referring additionally now to FIGS. 8A & B, an alternate
configuration of a downhole power generator 96 embodying principles
of the present invention is representatively illustrated. The power
generator 96 is similar in many respects to the power generator 26
described above, but differs in at least one substantial respect in
that it includes multiple power generating structures 98. The power
generating structures 98 are distributed circumferentially about a
central axial flow passage 100 formed through a housing assemble
102. Some of the benefits of the positioning of the structures 98
about the passage 100 are reduced flow restriction and improved
access to the flow passage 100 below the structures 98.
Each of the structures 98 is depicted in FIG. 8B as having a single
power generating assembly 104 within a nose 106 and attached to an
elongated member 108. Thus, the structures 98 are very similar to
the structure 42 described above. Note that each structure 98 may
include multiple ones of the power generating assemblies 104, and
any of the power generating assemblies 50, 58, 66, 68 described
above may be used for the assemblies 104 in the structures 98,
without departing from the principles of the present invention.
Fluid flow through the passage 100, either upwardly or downwardly
as viewed in FIGS. 8A & B, causes the structures to vibrate.
Vibration of the structures 98 causes the power generating
assemblies 104 to generate electrical power. The electrical power
is transmitted, via conductors 110, to a power storage and
conversion unit 112. The unit 112 may be connected to a separate
downhole tool, such as the valve 20 in the method 10, or a downhole
tool may be included in the power generator 96, such as the tool 80
in the power generator 26 described above.
Note that the power generator 96 does not include a lock or
inductive coupling, and the power generating structures 98 are not
retrievable from the power generator while it is downhole. It is to
be clearly understood, however, that these features of the power
generator 26 may be incorporated into the power generator 96
without departing from the principles of the present invention.
Referring additionally now to FIGS. 9 & 9A, an alternate
configuration of a nose 150 embodying principles of the present
invention is representatively illustrated. The nose 150 may be
substituted for either the nose 46 in the apparatus 26 or the nose
106 in the apparatus 96, or in other apparatus incorporating
principles of the present invention.
The nose 150 includes an elongated generally tubular body 152 and a
substantially solid end portion 154. The end portion 154 has a
lower linear edge or blade 156 formed thereon. Of course, it is not
necessary in keeping with the principles of the present invention
for the body 152 to be tubular, or for the end portion 154 to be
substantially solid.
In a preferred manner of using the nose 150, the end portion 154
faces into fluid flow through a housing, as would be the case if
the nose were substituted for either the nose 46 or 106 in the
apparatus 26 or 96 as described above. However, it is to be clearly
understood that the nose 150 and its end portion 154 may face in
the direction of the fluid flow, transverse to the fluid flow,
oblique to the fluid flow, or in any other direction, without
departing from the principles of the present invention.
It will be readily appreciated by one skilled in the art that fluid
flowing about the nose 150 will be deflected and will have its
momentum otherwise changed in a manner different from that caused
by fluid flow about the nose 46 or 106 described above. As a
result, the member 44 or 105 will be vibrated differently in
response to the fluid flow. This difference in vibration may be in
the amplitude or frequency of the vibration, or both. Thus, the
nose 150 provides a device for adjusting the amplitude and/or
frequency of vibration of the member 44 or 108 in response to fluid
flow through the housing 28 or 102.
It will further be readily appreciated that other elements of the
power generator 26 or 96 may be configured to produce differences
in the vibration of the member 44 or 108. For example, flow
deflectors (not shown) may be positioned within the housing
assembly 28 or 102 to create turbulence in, or otherwise change the
momentum of, fluid flowing through the housing assembly, the member
44 or 108 itself may be configured to deflect fluid flowing about
it, to such as by forming one or more flow deflectors on the
member, etc. Therefore, any manner of, or device for, changing the
momentum of fluid flowing through the housing 28 or 102, and any
manner of, or device for, altering the amplitude and/or frequency
of vibration of the member 44 or 108 in response to the fluid flow
may be utilized, without departing from the principles of the
present invention.
In FIGS. 10-12 are representatively illustrated additional
alternately configured noses 160, 162, 164. Each of these noses
160, 162, 164 may be used in place of the nose 46 or 106 of the
power generator 26 or 96. It is to be understood that the noses 46,
106 of the power generators 26, 96 and the alternate noses 150,
160, 162, 164 described herein are given merely as examples of the
wide variety of different nose configurations which may be used,
and as examples of the wide variety of methods of altering the
vibration of the member 44, 108 in response to fluid flow, in
keeping with the principles of the present invention, and are not
to be taken as limiting those configurations and methods.
Each of the noses 160, 162, 164 includes a generally tubular body
portion 166, 168, 170 and an end portion 172, 174, 176,
respectively. Preferably, the respective end portion 172, 174, 176
faces into fluid flow through the housing 28 or 102, but could face
in another direction if desired.
The end portion 172 of the nose 160 is generally cross- or X-shaped
when viewed from its downward end as depicted in FIG. 10. The cross
shape results from recesses 178 formed into the generally
cylindrical end portion 172. The end portion 174 of the nose 162
has a generally flat circular shape when viewed from its downward
end as depicted in FIG. 11. The end portion 176 of the nose 164 has
a generally spherical shape as depicted in FIG. 12.
It will be readily appreciated by one skilled in the art that the
various shapes of the end portions 154, 172, 174, 176 of the noses
150, 160, 162, 164 will produce correspondingly varied changes in
momentum of the fluid flowing about the noses. Thus, the noses 150,
160, 162, 164 will each produce a different vibration of the member
44 or 108 in response to the fluid flow through the housing, 28 or
102.
Referring additionally now to FIG. 13, another downhole power
generator 114 embodying principles of the present invention is
schematically and representatively illustrated. In the power
generator 114, a member is not vibrated laterally in response to
fluid flow as in the power generators 26, 96 described above.
Instead, the power generator 114 has a power generating structure
112 which includes a member or nozzle 116 which is vibrated axially
in response to fluid flow therethrough. The nozzle 116 may also be
described as a venturi, although it is not necessary in keeping
with the principles of the present invention for the vibrated
member in the power generator 114 to create an increase in fluid
velocity therethrough or to create a reduction in fluid
pressure.
The nozzle 116 is reciprocably disposed within a housing 118 of the
power generator 114. The nozzle 116 has a flow passage 120 formed
axially therethrough which is in fluid communication with a flow
passage 122 formed axially through the housing 118. Thus, the
housing 118 may be interconnected in the tubular string 14 in the
method 10, in which case fluid flowing through the tubular string
will also flow through the nozzle 116.
The nozzle 116 is configured so that it causes a change in pressure
in the fluid flowing through the passage 120. As depicted in FIG.
13, the passage 120 has a reduced diameter at an upper end of the
nozzle 116. It will be readily appreciated by one skilled in the
art that, as fluid flows upwardly through the passage 120, its
velocity will increase and its pressure will decrease due to the
reduced diameter of the passage 120 at the upper end of the nozzle
116. Thus, the shape of the nozzle 116 causes a differential
pressure across the nozzle as fluid flows therethrough.
The differential pressure across the nozzle 116 biases the nozzle
upwardly. Upward displacement of the nozzle 116 relative to the
housing 118 is resisted, however, by a spring or other bias member
124. It will be readily appreciated by one skilled in the art that
the differential pressure created across the nozzle 116 due to the
fluid flow therethrough is not constant, but continuously varies.
This varying differential pressure causes the nozzle 116 to vibrate
axially relative to the housing 118.
One or more piezoelectric crystals 126 (only one of which is shown
in FIG. 13) is positioned between the nozzle 116 and the housing
118 so that, as the nozzle 116 vibrates, strain is induced in the
piezoelectric crystal. In effect, the crystal 126 is repetitively
compressed between the nozzle 116 and the housing 118, thereby
causing the crystal to generate a corresponding repetitive
electrical output in response.
Although not shown in FIG. 13, the crystal 126 may be connected to
a power storage and/or conversion unit, such as the unit 76 of the
power generator 26, and the power generator 114 may include other
features of the power generators 26, 96. For example, the power
generator 114 could include an inductive coupling and lock so that
the structure 112 is retrievable from the power generator. Thus,
the specific construction and configuration of the power generator
114 may be changed, without departing from the principles of the
present invention.
Referring additionally now to FIG. 14, another downhole power
generator 130 embodying principles of the present invention is
schematically and representatively illustrated. The power generator
130 is similar in many respects to the power generator 114
described above, and so elements shown in FIG. 14 which are similar
to those previously described are indicated using the same
reference numbers.
The power generator 130 includes a power generating structure 132,
which in turn includes the nozzle 116. However, instead of the
piezoelectric crystal 126 of the power generator 114, the power
generating structure 132 includes a magnetostrictive material 134
and a coil 136. The magnetostrictive material 134 is positioned
between the nozzle 116 and the housing 118, and at least partially
within the coil 136. Of course, this configuration may be changed,
without departing from the principles of the present invention.
The nozzle 116 vibrates in response to fluid flow therethrough as
described above. Vibration of the nozzle 116 induces strain in the
magnetostrictive material 134, causing it to generate a magnetic
field about the coil 136. The magnetic field causes the coil 136 to
produce an electric current. Thus, the material 134 is repetitively
compressed between the nozzle 116 and the housing 118, thereby
causing the coil 136 to generate a corresponding repetitive
electrical output in response.
As with the power generator 114 described above, the power
generator 130 may be differently configured, may include a power
storage and/or conversion unit, and may include other features of
the power generators 26, 96, without departing from the principles
of the present invention.
Referring additionally now to FIG. 15, another downhole power
generator 140 embodying principles of the present invention is
schematically and representatively illustrated. The power generator
140 is similar in many respects to the power generators 114, 130
described above, and so elements shown in FIG. which are similar to
those previously described are indicated using the same reference
numbers.
The power generator 140 includes a power generating structure 142,
which in turn includes the nozzle 116. However, instead of
compressing a material or crystal between the nozzle 116 and the
housing 118, a magnet 144 is displaced relative to a coil 146. The
magnet 144 is attached to the nozzle 116 and the coil 146 is
attached to the housing 118, with the magnet being positioned
within the coil. Of course, this configuration may be changed,
without departing from the principles of the present invention.
The nozzle 116 vibrates in response to fluid flow therethrough as
described above. Vibration of the nozzle 116 displaces the magnet
144 relative to the coil 146, thereby producing an electric current
in the coil. Thus, as the nozzle repetitively displaces axially
relative to the housing 118, the coil 146 generates a corresponding
repetitive electrical output in response.
As with the power generators 114, 130 described above, the power
generator 140 may be differently configured, may include a power
storage and/or conversion unit, and may include other features of
the power generators 26, 96, without departing from the principles
of the present invention.
Referring additionally now to FIG. 16, an alternate embodiment of
the power generator 26, indicated as a power generator 200,
embodying principles of the present invention is representatively
and schematically illustrated. Only a portion of the power
generator 200 is depicted in FIG. 16, it being understood that the
remainder of the power generator is substantially similar to the
power generator 26 shown in FIGS. 2A-F and described above.
Additionally the power generating structure 42 of the power
generator 200 as illustrated in FIG. 16 utilizes the alternate nose
164 of FIG. 12 in place of the nose 46.
The power generator 200 includes a nozzle, venturi or member 202
which regulates a response of the power generating structure 42 to
the fluid flow (indicated by arrows 204 in FIG. 16) through the
passage 30, or, stated differently, the nozzle regulates the effect
the flow through the passage has on the power generating structure.
This result is accomplished in the embodiment depicted in FIG. 16
by increasing the flow area available for the flow 204 between the
nose 164 and the nozzle 202 when the flow rate increases and,
conversely, decreasing the flow area when the flow rate decreases.
However, it is to be clearly understood that this result may be
accomplished in a variety of manners, and the nozzle 202 may be any
other type of flow responsive vibration regulating member, without
departing from the principles of the present invention.
It will be readily appreciated by one skilled in the art that the
fluid flow 204 creates a generally upwardly biasing force on the
nozzle 202. A compression spring 206 exerts a downwardly biasing
force on the nozzle 202. Thus, the nozzle 202 is displaced upwardly
when the upwardly biasing force due to the flow 204 exceeds the
downwardly biasing force exerted by the spring 206. As shown in
FIG. 16, the nozzle 202 has been displaced somewhat upwardly
relative to the power generating structure 42, thereby increasing
the flow area between the nose 164 and the nozzle.
Regulation of the response of the power generating structure 42 to
variations in the flow 204, or the effect of variations in the flow
on the power generating structure, produces many benefits. For
example, it may be advantageous in terms of the amount of power
generated for the velocity of fluid flow about the nose 164 to
remain relatively constant, or to only vary within certain limits,
in order to maintain the power generating structure 42 vibrating
with maximum amplitude. As another example, an initial relatively
high fluid velocity about the power generating structure 42 may be
useful in initiating vibration of the structure in response to the
fluid flow 204, particularly when the flow rate is relatively
small. As yet another example, the nozzle 202 may vibrate in
response to the fluid flow 204 and the force exerted by the spring
206, and this vibration and its consequent effect on the fluid flow
between the nozzle and the nose 164 may, in turn, be utilized to
affect the vibration of the power generating structure 42. These
and many other benefits may be realized in the power generator 200,
and it is to be clearly understood that the benefits specifically
described above may or may not be attained in other power
generators embodying principles of the present invention.
Additionally, it is to be clearly understood that FIG. 16 depicts
only one manner in which the response of the power generating
structure 42 to variations in the flow 204, or the effect of
variations in the flow on the power generating structure, may be
regulated to beneficial effect. It will be readily appreciated that
a variety of means may be used to regulate fluid velocity,
turbulence, momentum, etc. about the power generating structure 42
(or within the power generating structures 112, 132, 142 of FIGS.
13-15), or to regulate the effect of such velocity, turbulence,
momentum, etc. on the power generating structures. For example, the
shape, mass or position of the noses 46, 106, 150, 160, 162, 164
could be altered, the mass, position or flow area through the
nozzle 116 could be altered, the spring rate of the springs 124,
206 could be varied, etc. Thus, the response of a power generating
structure to changes in fluid flow through a power generator may be
regulated in response to the fluid flow changes in any manner
without departing from the principles of the present invention.
Of course, a person skilled in the art would, upon a careful
consideration of the above description of representative
embodiments of the invention, readily appreciate that many
modifications, additions, substitutions, deletions, and other
changes may be made to these specific embodiments, and such changes
are contemplated by the principles of the present invention.
Accordingly, the foregoing detailed description is to be clearly
understood as being given by way of illustration and example only,
the spirit and scope of the present invention being limited solely
by the appended claims.
* * * * *